Shockproof switch



Nov. 19, 1946. J, w, MCCLAIN 2,411,447

SHOCKPROOF SWITCH Filed Sept. 2, 1944 Irwventor: Joseph W. McClain,

y His Attorney.

Patented Nov. 19, 1946 UNITED STATES PATENT OFFICE ZAllfid'l SHD JKPRQQFSVIIT CH New York Application September 2, 1944, Serial No. 552,406

2 Claims. I

M invention relates to shockproof switches, more particularly toshockproof electromagneticall operated switches, and has for its objectsimple, reliable and inexpensive switch in which the moving parts arestatically balanced so as to be free from the effects of shocks.

In carrying out my invention in one form, I provide a disc shaped membermounted for rotation on a central axis about which the disc isstatically balanced. One half of the disc is in the form of a peripheralstrip or bar which has at one end a portion made of magnetic material,the remainder of the strip and the disc being made of non-magneticmaterial. I further provide an operating coil surrounding the stripwhich, when energized, pulls the magnetic strip portion into anattracted position whereby the disc is rotated and switch meansconnected to the disc is moved between its operating positions.

For a more complete understanding of my invention, reference should behad to the accompanying drawing, the single figure of which is adiagrammatic representation of an electric switch embodying m invention.1

Referring to the drawing, in one form or" my invention I provide acircular or disc-like memher I which may be formed or cut from a plateof non-magnetic material, such as brass or a phenolic compound. One halfof the disc l is formed or cut away to leave a large aperture 2 and asemicircular peripheral strip or bar 3. The strip 3, furthermore, isprovided at one end with a portion 4 made of magnetic material whichextends throughout substantially one half the length of the strip.

The disc I is mounted for rotation on a pivot shaft 5 at its center,about which pivot shaft 5 the disc i statically balanced. This staticbalance, for example, may be obtained by adding suitable material ifrequired to the strip 3 to offset the greater weight of the oppositesolid half of the disc.

To efiect the rotation of the disc through a substantiall QO-degreeangle thereby to operate an electric switch 6, I provide a stationaryoperating 45 coil 1 which surrounds the strip 3. Preferably, the coil isprovided with a central bore 8 which is large enough to accommodatesubstantially one half of the length of the strip 3, the coil having alength sufficient to extend over substantially one half of the length ofthe strip 3. By means of suitable biasing means, such as a spring 9, thedisc I is biased to an angular position in which the non-magneticportion of the strip 3 extends through the coil. When the coil isenergized, the

,, switch 6 is mounted on one end of a bell crank Ill,

the opposite end of which is connected by means of a link H to a pivotl2 secured to the disc I a suitable distance from the pivot 5. As shown,the pivot I2 is in such a position that it lies on a lo radius extendingsubstantially at right angles with the link ll. Therefore, when the discis rotated clockwise to its attracted position, the pivot l2, in movingthrough a 90-degree angle, moves downward below the pivot shaft 5 into adead center position, i. e. parallel with a radius of the disc,

with respect to any force applied by the link i l to the disc andswitch. This rotation of the disc, it will be observed, moves the switchto its closed circuit position. Thus the disc itself is not onlystatically balanced about its pivot shaft 5, and therefore free from theefiects of shocks, but the disc is not affected in terms of rotation byany shock or other force applied to the disc by the switch. This isbecause any such force is applied directly to the shaft 5 without anycomponent producing rotation of the disc in either direction. Ifdesired, suitable stop means may be provided for limiting the rotationof the disc in each direction, especially stop means for positioning thedisc angularly in its attracted position so that the link ll extendalong a radius of the disc. As shown, the inner side I3 serves as a stopby engagement with the upper end of the coil to limit thecounterclockwise rotation of the disc by the biasing 5 spring 9, whilethe similar inner side M of the disc engages the lower end of the coilto limit the clockwise rotation of the disc by the coil.

While I have shown a particular embodiment of my invention, it will beunderstood, of course,

that I do not wish to be limited thereto since many modifications may bemade, and I therefore contemplate by the appended claims to cover anysuch modifications as fall within the true spirit and scope of myinvention.

1. A shockproof switch comprising a disc member made of non-magneticmaterial provided with a substantially semi-circular strip defining onehalf of the disc member, a portion of said strip being made of magneticmaterial, a central pivot for said disc member about which said discmember is statically balanced, a coil surrounding said strip, meansbiasing said disc member to a position in which the non-magnetic portionof said strip extends through said coil whereby when said coil isenergized said disc member is rotated substantially 90 degrees therebyto bring said magnetic portion of said strip into an attracted positionwith respect to said coil, circuit control means, a link connecting saidcircuit control means with said disc member, said link being connectedto a pivot on said disc member in such position that when said discmember is in said attracted position said link lies along a radius ofsaid disc member whereby a force applied by said link to said discmember is inefiective to produce rotation of said disc member.

2. A shockproof switch comprising a disc member made of non-magneticmaterial having a substantially solid semi-circular portion and aperipheral strip defining the opposite half of the disc, substantiallyone half of said strip being made of magnetic material, a central pivotfor said disc about which said disc is statically balanced, a coilsurrounding said strip and coextensive with substantially one half ofthe length of said strip, means biasing said disc to a position in whichsaid non-magnetic half of said strip extends through said coil wherebywhen said coil is energized said disc is rotated substantially 90degrees thereby to bring said magnetic portion of said strip into anattracted position inside of said coil, circuit control means, a linkconnecting said circuit control means with said disc, said link beingconnected to a pivot on said disc in such position that when said discis in said attracted position said link lies along a radius of said discwhereby a force applied by said link to said disc member is ineffectiveto produce rotation of said disc member.

JOSEPH W. MCCLAIN.

